PRELIMINARY STUDIES ON THE MECHANISM OF GLYPHOSATE TOLERANCE IN BEAN

Foliar absorption of glyphosate and the quantity translocated into root of tolerant and susceptible bean were determined by Liquid Chromatographic method, but no difference was found. After 72h and 120h of foliar treatment there was also no difference in glyphosate translocation. Protein content of EPSP synthase in extracts from tolerant and susceptible bean are 3.00 mg/mL and 3.08 mg/mL, respectively. Specific activity of EPSP synthase are 2.13 nmol·min -1·mg -1 protein and 1.97 nmol·min -1·mg -1 protein, respectively. But glyphosate inhibited EPSP synthase activity in tolerant and susceptible biotypes uneaqually. EPSP synthase activity of tolerant and susceptible biotypes was inhibited approximately 50% by 19.2 μmol/L and 6.3 μmol/L glyphosate, respectively. The current research has shown that difference between beans in glyphosate tolerance consist in the difference of EPSP synthase activity by glyphosate inhibition.